Contra Sola Scriptura
"But if I tarry long, that thou mayest know how thou oughtest to behave thyself in the house of God, which is the church of the living God, the pillar and ground of the truth."
There are some Christian confessions which claim the Bible to be the final authority on matters of faith and morals. As Catholics we believe Christ established the Catholic Church as the final authority on faith and morals. The belief in the Bible as the sole source of faith is unhistorical, illogical, fatal to the virtue of faith, and destructive to unity. It is unhistorical because the Catholic Church existed well before there was ever a New Testament and those who received the word of the Church did so solely on its authority(1 Thess 2:13). It is illogical because it says anything outside the scripture is not to be believed, yet this belief is not supported anywhere in scripture. It is fatal to the virtue of faith because faith consists in submitting and private interpretation consists in judging. In faith by hearing, the last word rests with the teacher; in private judgment it rests with the reader. It is destructive to unity because it accepts no human authority, and as a result, there are over 30,000 communities adhering to Sola Scriptura who disagree with one another (Mk 3:24). However, the Catholic Church which teaches the one and same Faith (Eph 4:5) throughout the whole world.
As a result the Church, to whom the transmission and interpretation of Revelation is entrusted, "does not derive her certainty about all revealed truths from the holy Scriptures alone. Both Scripture and Tradition must be accepted and honored with equal sentiments of devotion and reverence."
The Tradition here in question comes from the apostles and hands on what they received from Jesus' teaching and example and what they learned from the Holy Spirit. The first generation of Christians did not yet have a written New Testament, and the New Testament itself demonstrates the process of living Tradition.
Read the Scripture within "the living Tradition of the whole Church". According to a saying of the Fathers, Sacred Scripture is written principally in the Church's heart rather than in documents and records, for the Church carries in her Tradition the living memorial of God's Word, and it is the Holy Spirit who gives her the spiritual interpretation of the Scripture ". . . according to the spiritual meaning which the Spirit grants to the Church".
Mt. 18:17-19 - Jesus exhorts people to seek the Church as a final authority. He does not say scripture.
Jn. 21:25; 3 Jn. 1:13 - John does not write everything about the Faith in scripture. The rest was transmitted orally.
1 Cor. 11:2; 2 Thess. 2:15; 2 Thess.3:6 - Paul instructs the Church to hold fast to the traditions that were handed down.
1 Tim. 3:15 – Paul says the Church, not scripture, is the pillar and foundation of the truth.
2 Pet 1:20 - Peter says scripture should not be subject to one’s own private interpretation.
Tradition & Fathers
"Whenever anyone came my way, who had been a follower of my seniors, I would ask for the accounts of our seniors: What did Andrew or Peter say? Or Phillip or Thomas or James or John or Matthew, or any of the Lord’s disciples? I also asked: What did Aristion and John the Presbyter, disciples of the Lord say. For, as I see it, it is not so much from books as from the living and permanent voice that I must draw profit."
"The apostles at that time first preached the Gospel but later by the will of God, they delivered it to us in the Scriptures…"
"When heretics show us the canonical Scriptures, in which every Christian believes and trusts, they seem to be saying: 'Lo, he is in the inner rooms [the word of truth] ' (Mt 24.6). But we must not believe them, nor leave the original tradition of the Church, nor believe otherwise than we have been taught by the succession [of bishops] in the Church of God."